Per Japanese blog Mac Otakara, sources have have stated that Apple is testing a MacBook Air with an A5 processor, the same CPU powering the iPad 2 as well as a Thunderbolt port. While the machine performed “better than expected” according to their source, the article says it’s unclear whether this test machine was running Mac OS X or iOS.

If Apple has indeed built such a device, it’s unlikely the company intends to put it on the market. While the A5 processor is powerful enough under iOS, in terms of raw performance it pales in comparison to even the least powerful Intel chips, the A5’s Geekbench score standing around 720, while the lowest-rated MacBook Air processor scored over 2000. Benchmarks don’t tell the whole story, of course, but they’re a fairly reliable predictor of the general performance you can expect to get from a machine.

From what we’ve seen of Mac OS X Lion thus far, it already looks as though Apple’s looking at ways of merging OS X and iOS as far as the software’s concerned. If Mac Otakara’s sources are correct, it seems it’s just a matter of time before the hardware follows.